Year	Percent
1990	71.09
1991	71.3
1992	71.25
1993	71.41
1994	71.62
1995	71.86
1996	72.05
1997	72.3
1998	72.38
1999	72.42
2000	72.43
2001	72.88
2002	73.31
2003	73.74
2004	74.15
2005	74.55
2006	74.95
2007	73.24
2008	73.92
2009	74.07
2010	74.09
2011	74.04
2012	71.07
2013	71.18
2014	73.38
2015	68.99
2016	69.81
2017	71.04
2018	74.04
2019	74.21